Polymethine compounds and process for preparing them



I Patented Feb. 13, 1945 PoLYME rHmE COMPOUNDS AND PROCESS FOR PREPARING THEM.

Frank L. White, Rochester, N. Y,., assignor to Eastman Kodak Company, Rochester, N. Y., a Y corporation'of New Jersey w I No Drawing.

Application December 4, 1940, Serial No. 368,517

9 Claims. .(Cl. 2 -240) This invention relates to polymethine compounds and to a process for preparing them. 'It is known that certain cyclammonium quaable by my process aresensitizers of photographic silver-halide emulsions. j

ternary salts'containing a'fl-arylaminovinyl group p in the alpha or'ga'r'n'maposition, i. e., in one of the so-called reactive 'positions, can-be prepared by condensing diar'ylfo'rmamidines with cyclam- 'monium"quaternar'ysalts containing a reactive methyl group." If this condensationis I carried out in the presence of an anhydride. of a monocarboxylic acid, such asacetic anhydride, aN-acyl B-arylaminovinyl compound is formed. It is also known that certain cyclammonium quaternary salts containing an varylamino-l,3-butadienyl group in areactive position can bepre'pared by condensing, in the presence of a basic condensing agent; *1-arylamino-3-arylimino propene salts with cyclammonium quaternary salts containing areactive methyl group. If this condensation is carried out in the presence of ananhydride of a monocarboxylic acid, -a-N-acyl .arylamino-L3- butadienyl compound is formed; It is further known that certain cyclammonium quaternary salts containing an arylamino-1,3,5-hexatrienyl group in a reactive-position can be prepared by condensing, in' the presence of a basic condensing agent, l-ar ylamino-5-arylimino-1.3-pentadiene salts with cyclammonium quaternary salts containinga reactive [methyl group. If "this condensation is carried out in'the presence of an anhydride of a monocarboxylic acid, a N-facyl arylamino l,3,5-hexatrienyl compound is formed.-

Several of these polymethine compounds, in-' cluding some of the acylated, have a weak to moderatesensitizing' action on photographic silvar-halide emulsions. h w I The above methods of preparation of the polymethine compounds are not especially well adapted to the production ofcomp-oundswherein the arylamino portion'orthe vinyl, the 1,3-buta dienyl or the 1,3,5-heXatrienyl group carries substituents, such as halogen, alkyl, alkoxy or dialkyla'mino, on the aryl nucleusowingto the unavailability of the necessary starting materials.

This is especially true among the 1,3-butadienyl and 1,3,5-hexatrienyl compounds, where such substituted derivatives are unknown.

I have now found anew methodfor producing c-arylaminoviuy1, arylamino-LS-butadienyl and aryla'mino-1,3,5-hexatrienyl compounds. More-' over, my new method allows of the ready pro-' duction of the aforesaidcompounds carrying substituents on the aryl nucleus. I have also found thatsome of thepsubstitutedderivatives obtain- It is, accordingly, an object of myinvention to provide a newprocess'for preparing polymethine compounds. Another object is to prov1de new polymethine compounds. A further ob ect is to provide photographic emulsions sensitized withsuch new compounds. Other objects will become apparent hereinafter. I

In accordance with my invention, I react a primary aromatic amine with a cyclammonium quaternary salt containing-in a reactive position, a member selected from the group consisting of N .acyl parylaminovinyl groups, N-acyl arylamino- 1,3-butadienyl groups- .and N- acyl arylamino- 1,3,5-hexatriehyl groups. Secondary aromatic amines. such as methylaniline, will not undergo a similar reaction. I

I have found it advantageous to employ from about 1%; toabout 2- molecular proportions of prima'ry aromatic amine for each'molecular proportion'of N-acyl aryl'amino compound. I have also found it advantageous to effect the reactions in the presence of an alcohol, such as an alcohol of the formula 'CnH2n+1OH where n represents a positive integer offrom one to three. Heat accelerates the reactions.

The following examples will serve to my new process. 0

Example 1-.2-(2-am'li novinyl) benzoth azole ethv 1.12 g. (I mol.) of 2-(2-acetanilidovinyl) benzothiazole ethiodide and 0.3 g. (1.25 mol.) of aniline were placed in 10 cc. of absolute ethyl alcohol. The mixture was boiled, under reflux, for 20 minutes; The mixture was then cooled and stirred with 200 cc; 'ofdie'th'yl; ether; The resulting suspension was chilled 'for'j'several hours at 0 -C. The solid polymethine compound was collected on a filter. It was removed from the filter and stirred with boiling acetone. The resulting sus- Dension'was chilled for several hours at 0 C'. The polymethine compoundwas again filtered off and washed with acetone- After two recrystallizations from methyl alcohol, the compound was obtained, in 54% yield, a's-brownish needles having a blue reflex and melting at 265 to 266 C. with decomposition. The compound sensitized a photoillustrate position.

Example 1.2 g. (1 mol.) of 2-(4-acetani1ido-1,3-butadienyl) benzothiazole ethiodide and 0.35 g. (1.25 mol.) of o-toluidine were placed in 15 cc. of absolute ethyl alcohol. The mixture was boiled, under reflux, for 30 minutes. The reddish reaction mixture was cooled and stirred with 200 cc. of diethyl ether. The resulting suspension was chilled for ,2 hours at C. The polymethine compound was collected on a filter and washed with methyl alcohol. After three recrystallizations of the compound from methyl alcohol (45 cc. per gram of compound), the compound was obtained as dull reddish crystals having a blue reflex and melting at 212 to 214 C., with decom- The compound sensitized a photographic gelatino-silver-bromiodide emulsion strongly out to about 610 mu with a maximum at 540 mu.

Example 32- [4-(o-nitroanilino) -1,3-butadz'enyllbenzothiazole ethiodide s NO \/1 95% ethyl alcohol the compound was obtained in 17% yield as minute dark crystals melting at 251 to 252 C., with decomposition. The compound desensitized a photographicgelatino-silyer-bromiodide emulsion.

Example 4-2-[4-(23-Chl070l17lili1l'0) -1,3-butadienyllbenzothiazole ethiodide 1.2 g. (1 mol.) of 2-(4-acetanilido-1,3-butadienyD-benzothiazole ethiodide and 0.68 g. (2 mol.) of p-chloroaniline were placed in cc. of absolute ethyl alcohol. The resulting mixture was boiled, under reflux, for 20 minutes. The reaction mixture was then cooled and stirred with 100 cc. of diethyl ether, and the resulting suspension was chilled for 3 hours at 0 C. The polymethine compound was collected on a filter and washed with acetone. After two recrystallizations from methyl alcohol, the compound was obtained in 64% yield as purple crystals melting at 232 to 233 C., with decomposition. The compound sensitized a photographic gelatino-silverbromiodide emulsion fairly strongly out to about 605 mu with a maximum at about 540 mu.

Example 5-2-[4-(10-anisidino) -1,3 butadienyll benzothiazole ethiodide s /1\ 1 1.2 g. (1 mol.) of 2-(4-acetanilido-L3-butadienyl) benzothiazole ethiodide and 0.62 g. (2 mol.) of p-anisidine were placed in 10 cc. of absolute ethyl alcohol. The resulting mixture was boiled, under reflux, for 20 minutes. The latter reaction mixture was cooled and stirred with cc. of diethyl ether, and the resulting suspension was chilled for 3 hours at 0 C. The polymethine compound was collected on a filter and washed with acetone. After two recrystallizations from methyl alcohol, the compound was obtained in 52% yield, as minute dark blue needles melting at 214 to 215 C., with decomposition. The compound sensitized a photographic gelatino-silverbromiodide emulsion fairly strongly to about 625 mu with no well-defined maximum.

Example 6-2-[4-(p-naphthylamz'no) -1,3 butadz'enyl] beneothiazole ethiodide Cz 5 I 1.2 g; (1 mol.) of 2-(4-acetanilido-1,3-butadienyl) -benzothiazole ethiodide and 0.48 g. (1.25 mol.) of ,S-naphthylamine were placed in 10 cc. of absolute ethyl alcohol. The mixture was boiled, under reflux, for 20 minutes. The mixture was then cooled and stirred with 200 cc. of

diethyl ether. The resulting mixture was chilled for several hours at 0 C. The polymethine compound was filtered ofl and stirred with boiling acetone. The resulting suspension was chilled for several hours at 0 C. The compound was again collected on a filter and washed with acetone. After two recrystallizations from methyl alcohol, the compound was obtained in 29% yield as dark crystals having a brass colored reflex and melting at 241 to 242 C., with decomp0- sition. The compound sensitized a photographic gelatino-sfiver-bromiodide emulsion strongly to about 630 mu with an ill-definedymaximum at about 560 mu.

Example 7-2- [4-(o-phenetidino) -1,3-butaolien yl] -benzothiaz0le. ethiodide 1.2 g. (1 mol.) of 2-(4-acetanilido-L3-butadienyD-benzothiazole ethiodide and 0.43 g. (1.25

mol.) of o-phenetidine were mixed together in 15 cc. of absolute ethyl alcohol. The resulting mixture was boiled, under reflux; for 30 minutes. The reaction mixture was cooled and stirred with 200 cc. of diethyl ether. The resulting suspension was chilled for severalhours at l)"v C. The poly methine compound was then collected on a filter and washed with methyl alcohol. After three recrystallizations. from methyl alcohol, the compound was obtained as dark blue crystals melting at 224 to 225 0., with decomposition. The compound sensitized a gelatin'o-silver-bromiodide emulsion fairly strongly out to about 615 mu with no well-defined maximum.

The polymethine compound was collected on a iilter and washed with'alcohol. After two re,-

lute ethyl alcohol.

4.6g. (1 incl.) of 2-(4 acetanilido-l,3 butadie'nyl') -benz'oxazole ethiodide and 1.86 g'. (2 mol.) of aniline'were mixed together in 20 cc. of abso- The'resulting mixture was boiled, under reflux, for 20 minutes. The reaction mixture was then stirred with 200 cc. of ether, and the resulting suspension was chilled for several hours at C. The polymethine compound was filtered off and stirred with boiling acetone. The acetone suspension was chilled for several hours at 0 C. The polymethine' compound was again filtered ofi and'washed with acetone. After three recrystallizations, two from ethyl alcohol and a third from acetone, the compound was obtained, in 3% yield, as reddish needles having a blue reflex and melting at 188 to 190 C., with decomposition. The compound sensitized a photographic gelatino-silver-brorniodide emulsion fairly strongly out to about 550 mu with a maximum atv about 515 mu. In a' similar manner 2-(4-anilino-L3-butadienyl) -a-naphthoxazole ethiodide was obtained,

. in 25% yield, after three recrystallizations from crystallizations from methyl alcohol, the sem pound was, obtained, in45% yield, as dark green crystals Imelting at 262 to 263 C., with decomposition. The compound sensitized a gelatinosilver-bromiodide emulsion only slightly 'out'to about 600 mu. 7 I 7 Example 9-244"- (a -na4ahthothiaaolylamirt0) v l,3-b utadienyll -benz0thiazole ethiodide 0.93 g. (1 mol.) or 2-(4-acetanilido-L3-butadienyl) -benzothiazole-ethiodide and 1.2 g. (3 moi.) of 2-amino-e-naphthothiazole were 'mixed together in 10 cc. of absolute ethyl alcohol. The

poundwas obtained, in 19% yield, asgreen crystals melting at 234 to 235 0., with decomposition. The compound sensitized a' photographic gelatino -silver-bromiodide emulsion fairly strong- 1y out to about 670 mu with maxima at 540 rim and at 620 mu.

Example 10r-.-.2-(4-anilino-1,3-butadicnyl) omeoxazole ethiodide U 95% ethyl alcohol as light reddish crystals melting at 163 to 165 C., with decomposition. This compound sensitized a photographic gelatinosilver-bromiodide emulsion strongly out to 580 mu with a maximum at about 530 mu.

Example 11-2- (4-anz'lino-1,3-butadienyl) 4 benzoseleneeole ethiodide l 6 l 2o-oH=oH-oH=oH-NH- 1.3 g. (1 'mol.) of 2-(4 acetanilido-l,3-buta 'dienyD-benzoselenezole ethioclide and 0.3 .g.

(1.25 mol.) of aniline were mixed together in 15 cc. of absolute ethyl alcohol. The resulting mixture was boiled, under reflux, for minutes. The reaction mixture was then cooled and stirred with 200 cc. of diethyl ether. The resulting suspension was chilled for several hours at 0 C. The polymethine compound was then filtered off and-stirred with boiling acetone. The resulting suspension was chilled for several hours at 0 C.',

and the p-olymethine compound was again filtered on and washed with acetone. After two recrystallizations from methyl alcohol, the compound was obtained, in 71% yield, as dark needles having a green reflex and melting at 225 to 226 0., with decomposition. The compound sensitized a photographic gelatino-silver-bromiodide emulsion fairlystrongly out to 620 mu with a maximum at about 560- mu.

In a similar manner 2-('4-anilino 1,3-butadienyl)- 8-naphthothiazole ethiodide' was obtained after ,two recrystallizations from methyl alcohol, in yield, as dark needles having 'a double blue and green reflex and melting at 232 to 233 0., with decomposition. The compound sensitized a photographic gelatino-silverbromiodide emulsion weakly out to about 620 mu with no well-defined maximum.

Example 12-.2 -(6-anilino-1,3,5-hea:atrienyl) 1.25 g. (1 mol.) of 2-(G-acetanilldo-l,3,5-hexatrlenyD-benzothiazole ethiodide and 0.3 g. (1.25 mol.) of aniline were mixed together in cc. of absolute ethyl alcohol. The resulting mixture was boiled, under reflux, for minutes. The reaction mixture was then cooled and stirred with 200 cc. of diethyl ether. The resulting suspension was chilled at 0 C., for several hours. The polymethine compound was filtered ofi and stirred with boiling acetone. The resulting suspension was chilled for several hours at 0 C. The polymethine compound was again filtered ofi and washed with acetone. After two recrystallizations from methyl alcohol, the compound was obtained, in 26% yield, as minute green needles melting at 161 to 163 C., with decomposition. The compound sensitized a gelatino-silverbromiodide emulsion weakly from about 580 mu to about 690 mu with a maximum at 660 mu.

In a manner similar to that illustrated in Example 1, 2-(2-anilinovinyl)benzothiazole phenio-' dide can be prepared from 2- (Z-acetanilidovinyl) benzothiazole pheniodide. This acetanilido compound can be prepared as described in the co- .pending application of L. G. S. Brooker and W. W. Williams, Serial No. 353,500, filed August 21, 1940, by condensing Z-methylbenzothiazole pheniodide with diphenylformamidine, in the presence of acetic anhydride. 2-methylbenzothiazole pheniodide can be prepared as also described in the aforesaid Brooker and Williams application, by hydro-lyzing 2-dicarbethoxymeth ylene-3-phen ,'lbenzothiazo1ine, in the presence of hydrochloric acid.

Those of my new polymethine compounds containing phenylamino-l,3-butadienyl and-phenylamino-1,3,5-hexatrienyl groups in which the phenyl nucleus carries a halogen atom or an alkyl or alkoxy group, are, in general, fairly strong sensitizers of photographic emulsions.

to be strong sensitizers. The same is true of those of my polymethine compounds containing a 3- In :1 fact, in some cases, the compounds can be said reactive position, a member selected from the group consisting of .anilinovinyl groups, anilino- 1,3-butadienyl groups and aniline-1,3,5-hexatrienyl groups, can be replaced by certain other amino groups by treating the cyclammonium quaternary salts with certain strong basic amines such as N, N-dialkyl-p-phenylenediamines and piperidine. The following example illustrates the replacement:

Example 13-2-[4-(p-diethylaminoanilino) -1,3-

butadienyl]'benzothiazole ethiodide pension was chilled-"at 0C. The polymethine compound was collected on a filter and' washed with acetone. After two recrystallizations from absolute ethyl alcohol, the compound was obtained,-in 37% yield, as dark blue crystals melting at 224.to 225 C.,'with'd composition; The compound sensitized a photographic gelatino-silver-bromiodide emulsion Weakly to about 710 mu with no well defined maximum.

In the preparation of photographic emulsions containing the herein described polymethine compounds; it is only necessary'to disperse the compounds in the emulsions. It is convenient to add the compounds from solutions in appropriate solvents. Methanol has proven satisfactory as a solvent for the compounds.

Sensitization by means of these compounds is, of course, primarily directed to the ordinarily employed gelatino silver halide developing out emulsions, The compounds are advantageously incorporated in the washed,-finished emulsions and should, of course, be uniformly distributed throughout the emulsions.

' The concentration of these compounds in the emulsion: can vary widely, i. e., fromabout 5 to about mg. per liter of flowable emulsions. The concentration of the compound will vary according to the type of light-sensitive material in the emulsion and according to the effect desired. The suitable and most economical concentration for any given emulsion will be apparent to thoseskilled in the art upon making the ordinary tests and observations custpmarily used in the art of emulsion making.

T prepare a gelatino-silver-halide emulsion sensitized with one of these compounds, the following procedure is satisfactory. A quantity of the'compound is dissolved in methyl alcohol or other suitable solvent, and a volume of this solution (which may be diluted with water) containing from 5 to 100 mg. of compound is slowlyadded to about 1,000 cc. of gelatino-silver-halide emulsionwith stirring. Stirring is continued until the compound is uniformly distributed throughout the emulsion. With most of my new sensitizing compounds, 10 to 20 mg. of compound per liter of emulsion sufiices-to produce the maximum-sensitizing effect with the ordinary gelatino-silverbromiodide emulsions.

The above-statements are only illustrative and are not to be understood as limiting my invention, as it will be apparent-that these compounds can be incorporated by other methods in any of the photographic silver-halide emulsions customarily employed in the art. For instance: the compounds may be incorporated by bathing a plate or film upon which an emulsion has been coated in a solution of the compound in an appropriate solvent. Bathing methods, however, are not to be preferredordinarily.

What I claim as my invention and desire to be secured by Letters Patent of the United States is:

1. A process for preparing polymethine compounds comprising reacting a primary aromatic monoamine; with a cyclammonium quaternary salt of the type used in cyanine dyes containing, in a reactive position a member, selected from the groupconsisting of N-acyl pi-arylaminovinyl groups, N-acyl arylamino-LB-butadienyI groups and N-acyl arylamino-1,3,5hexatrieny1 groups.

2. A-process for preparing polymethine com pounds comprising reacting a primary monoamine of the benzene series with a cyclammonium quaternary salt of the type used in cyanine dyes containing, in a reactive position, a member selected from the group consisting of N-acyl parylaminovinyl groups, N-acyl arylamino-1,3- butadienyl groups and N-acyl ary1amino-1,3,5- hexatrienyl compounds. l

3. A process for preparing polymethine compounds comprising reacting a primary aromatic monoamine of the naphthalene series With a cyclammonium quaternary salt of the type used in cyanine dyes containing, in a reactive position,

- a member selected from the group consisting of N-acyl p-arylaminovinyl"groups, N-acyl arylamino-1,3-butadienyl groups andN-acyl ary1- amino-1,3,5-hexatrienyl groups.

4. A process for preparing polymethine'compounds comprising reacting a primary monoamine of the benzene series with a cyclammonium quaternary salt of the type used in cyanine dyes containing, in a reactive position, a N-acyl parylamino vinyl group.

5. A process for preparing polymethine compounds comprising reacting a primary monoamine of the benzene series with a cyclammonium quaternary salt of the type used in cyanine dyes containing, in a reactive position, a N-acetyl 19- arylamino vinyl group.

6.,A process for preparing polymethine compounds comprising reacting a primary monoamine of the benzene series with a.- cyclammonium quaternary salt of the type used in cyanine dyes containing, in a reactive position, a N-acetyl anilinovinyl group.

'7; A process for preparing polymethine compounds comprising reacting a primary monoamine of the naphthalene series with a cyclammonium quaternary salt of the type used in cyanine dyes containing, in a reactive position, a

N-acyl p-arylaminovinyl group. 

